As a method for producing a molded article of inorganic solid powder such as metal powder or ceramic powder, a method is known in which inorganic solid powder is dispersed in a thermoplastic binder and a lubricant to form a composition for molded article production, then the composition is subjected to preliminary molding by injection molding, and the resulting pre-molded article is heated to decompose and volatilize the components other than the inorganic solid powder present in the molded article in order to be degreased and is calcined to give a molded article that is a sintered body.
Stearic acid, which has been used heretofore as the aforementioned lubricant, decomposes at relatively low temperatures, and is thus problematic in that it decomposes while being kneaded with inorganic solid powder and a thermoplastic binder and results in poor kneading. Accordingly, a method that uses behenic acid, which has a higher decomposition temperature, has been proposed (see patent literature 1).
Although problems such as poor kneading can be solved by the method of patent literature 1, since behenic acid has a structure having a long chain alkyl group, its compatibility with a thermoplastic binder may be insufficient depending on the kind of the thermoplastic binder.
Also, a method is known in which a metal nanoparticle-containing dispersion is applied to a substrate so as to form a pattern, and calcined at a temperature as low as, for example, 300° C. or lower to form a conductive layer having a fine pattern composed of a sintered body layer in which the particles are aggregated to each other (see patent literature 2). Patent literature 2 states that a rosin derivative, which serves as a supply source of hydrogen atoms, is introduced to the metal nanoparticle-containing dispersion to remove the oxide layer on the metal nanoparticle surface, thus giving a dense sintered body. However, the method of patent literature 2 involves low-temperature calcination, and thus the rosin derivative in the dispersion does not thermally decompose sufficiently and remains as an impurity in the sintered body. Therefore, the method is problematic in, for example, resulting in conduction failure and a poor appearance.